The Role of Antivirals in the Management of Neuropathic Pain in the Older Patient with Herpes Zoster

Abstract

Herpes zoster has been known since ancient times. It is a ubiquitous disease, occurring sporadically without any seasonal preference and is caused by the varicella-zoster virus. It may be defined as an endogenous relapse of the primary infection varicella. Herpes zoster is characterised by typical efflorescences in the innervation region of a cranial or spinal nerve and starts and ends with pain of varying intensity. Currently, several antiviral drugs are approved and many studies have shown that antiviral therapy, started early in the course of disease, can significantly reduce the risk and the duration of postherpetic neuralgia in elderly patients. The effects of all antivirals discussed in this article, given either orally or intravenously, are comparable with regards to the resolution of virus replication, prevention of dissemination of skin lesions and reduction of acute herpes zoster pain. Valaciclovir (valacyclovir), famciclovir and brivudine (brivudin) are comparably effective in the reduction of the incidence and/or prevention of zoster-associated pain and postherpetic neuralgia. Brivudine 125mg once daily is as effective as famciclovir 250mg three times daily in reducing the prevalence and the duration of zoster-associated pain and postherpetic neuralgia, especially if therapy is combined with a structured-pain therapy. The intensity of the therapy for pain should depend on the intensity of the pain that it is treating. Famciclovir and brivudine offer an advantage over other antivirals because they are administered less frequently; this is particularly relevant for elderly patients who may already be taking a number of medications for other diseases. Therefore, antiviral therapy in combination with adequate pain management should be given to all elderly patients as soon as herpes zoster is diagnosed.

FV‐100 versus valacyclovir for the prevention of post‐herpetic neuralgia and the treatment of acute herpes zoster‐associated pain: A randomized‐controlled trial

“…It is evident that a drug with greater antiviral activity, better pain relief, and a more simplified dosing regimen represents a significant unmet medical need. Brivudine is also available in some countries for treating shingles …”

The Neurological Safety of Intrathecal Acyclovir in Rats

“…Antiviral agents are actually effective to control zoster-related pain and to prevent its complications. Antiviral agents attenuate the severity of zoster, the duration of viral shedding, acute pain, rash healing, and the incidence of PHN (1,(25)(26)(27)(28)(29). Acyclovir is a synthetic acyclic purine nucleoside analogue derived from guanine and used in the treatment of herpes simplex, herpes zoster, and varicella zoster virus infections.…”

Functional Neuroanatomy of Pain

“…Patients with PHN do not respond to nonsteroidal and anti-inflammatory drugs, and resistance or insensitivity to opiates is common (Bowsher 1997;Ossipov et al 2000;Kanazi et al 2000;Panlilio et al 2002;Dworkin and Schmader 2003;Pappagallo and Haldey 2003;Harden 2005). Recent research (Panlilio et al 2002;Dworkin and Schmader 2003;Lilie and Wassilew 2003) has shown that antiviral therapy can significantly reduce the risk and duration of postherpetic neuralgia in elderly patients, provided that treatment is started early in the course of disease (Jung et al 2004).…”